Rabbit study offers clues to massage benefits

NEW YORK (Reuters Health) - Massage helps people
feel better after strenuous exercise by actually pushing the
inflammation out of stressed muscles, new research in animals
suggests.

Dr. Timothy A. Butterfield of the University of Kentucky in
Lexington and his colleagues found "striking" differences
between rabbit muscles that underwent massage-like loading
immediately after exercise compared to muscles that weren't
massaged. "The muscle was able to produce a greater force than
the non-massaged control limbs and it also looked a lot better,"
Butterfield told Reuters Health in an interview.

Athletic trainers and physical therapists frequently use
massage to help athletes recover muscle function, he and his
colleagues note in their report in Medicine & Science in Sports
& Exercise. But while people say they feel better after massage,
little research has been done on what is actually happening
within their muscles, Butterfield said.

To investigate, he and his colleagues developed an animal
model of strenuous eccentric exercise, which requires muscles to
contract and lengthen at the same time. Some examples of
eccentric exercise include actions of the hamstrings and
quadriceps when a runner decelerates, as well as spinal muscle
movements that occur when a person carrying an object bends over
to set it down, Butterfield explained.

The researchers used machines to move the lower limbs of
anesthetized rabbits in a way that mimicked a human lifting very
heavy weights. For people, the researcher said, this is the type
of exercise that results in "really tight soreness, pain" in the
muscles. Then one of each animal's legs was massaged with a
computer-driven wheel immediately after exercise, while the
other leg was not.

Mechanical tests found the massaged limbs recovered strength
faster than the non-massaged limbs. And when Butterfield and his
team examined the animals' muscles under a microscope, they
found less swelling, inflammation, and tissue damage in the
limbs that had been massaged. Massaged muscle also weighed 8
percent less.

Butterfield and his colleagues suggest that massage may
lessen the movement of white blood cells into muscle tissue,
which would in turn cut down on tissue damage by reducing
oxidative damage these cells can cause. "However, this
hypothesis requires further testing," they write, noting that
the rabbit model used in the study isn't appropriate for "direct
translation" to humans.

He and his colleagues are now planning additional research in
humans to further investigate mechanisms of massage benefit, and
animal studies to examine what's happening to massaged cells at
the molecular level.